Climatologists from all over the world will be meeting in Paris later this month to discuss extreme weather -- heavy rains, flooding, high heat and lack of rain, cyclones, wind waves, storm surges and so on -- and what they can do about them: How these events can be measured, compared to each other and used to predict future weather.

The scientists are concerned because there were several extreme events around the world this year, some happening at the same time -- the extraordinary heatwave and wildfires in Russia, monsoons and flooding in Pakistan, landslides caused by heavy rain in China, and the separation of a large iceberg from the Greenland ice sheet. Add to these the droughts and fires in Australia, and a record number of hot days on the East coast of the U.S.

So far, hundreds of people have been killed, and millions have been displaced or lost their homes.

Climate extremes have always existed, but all the events cited above compare with, or exceed in intensity, duration or geographical extent, the previous largest historical events. According to Roshydromet, studies of the past climate show no record of similar high temperatures since the tenth and eleventh centuries in Ancient Russia.

The occurrence of all these events at almost the same time raises questions about their possible linkages to the predicted increase in intensity and frequency of extreme events, for example, as stipulated in the IPCC Fourth Assessment Report published in 2007. The Report stated that “…the type, frequency and intensity of extreme events are expected to change as Earth’s climate changes, and these changes could occur even with relatively small mean climate changes. Changes in some types of extreme events have already been observed, for example, increases in the frequency and intensity of heat waves and heavy precipitation events” (Summary for Policy Makers, WG I, FAQ 10.1, p. 122).

NASA's Goddard Space Flight Center, meanwhile, has updated its analysis of global temperature changes on the Earth's surface and finds that they've risen as fast in the last decade as they have in the previous two decades. This year the mean temperature (as measured by instrumental data) over 12 consecutive months set a record high.

NASA scientists submitted a paper describing the changes to Reviews of Geophysics that describes human-made climate change as "an issue of surpassing importance to humanity, and global warming (as) the first order manifestation of increasing greenhouse gases that are predicted to drive climate change."

The picture, from Goddard, is a map of world surface temperatures in July compared to the average temperature in July from 1951-1980.